Organic Light Emitting Diode (OLED) displays are widely used on a variety of electronic products due to its many advantages, such as all-solid state, self-luminous, high resolution, high brightness, high luminous efficiency, fast response, wide operating temperature range, low driving voltage, low power consumption, etc. However, organic light emitting components in OLED displays are vulnerable to oxygen and water vapor, and a reason that the OLED life span is short is the oxidative damage caused by the combination of the organic light emitting components and oxygen or water vapor. In this case, packaging processes are necessary for the OLED life span.